Question

def longest(string):
    start=0;end=1;i=0;
    while i<len(string):
        j=i+1
        while j<len(string) and string[j]>string[j-1]:
            j+=1
        if end-start<j-i:
            #update if current string has greater length than
            #max start and end
            end=j
            start=i
        i=j;
    avg=0
    for i in string[start:end]:
        avg+=int(i)
    print('The longest string in ascending order is',string[start:end])
    print('Teh average is',avg/(end-start))


s=input('Enter a string')
longest(s)
 

i need a definition and explanation of this code that how it works?

Answer 1

DEFINITION: This function will give you the longest substring which will be an increasing number.

I will explain with some examples below.

PLEASE FOLLOW THE COMMENTS IN THE CODE TO UNDERSTAND HOW EACH LINE WORKS,

def longest(string):
    # Let the starting and ending indices that are largest number is 0 and 1
    start = 0
    end = 1

    i = 0
    # Start from 0 to end of the string
    while i < len(string):
        j = i + 1
        # Again take a loop j=i+1 to end of string or
        # if it violates the condition of increasing order, break out of the loop
        while j < len(string) and string[j] > string[j - 1]:
            j += 1
        if end - start < j - i:
            # update if current string has greater length than
            # max start and end
            end = j
            start = i
        i = j

    # Here we have the start and end indices of the longest possible number
    avg = 0
    # So, calculate the average here.
    # First sum all the numbers and divide it by (end-start)
    for i in string[start:end]:
        avg += int(i)
    print('The longest string in ascending order is', string[start:end])
    print('The average is', avg / (end - start))


# Read Input
s = input('Enter a string')
# Call the function and pass the user-entered string
longest(s)

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sample OUTPUTS